merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/compat/fopen.c

@@ -0,0 +1,37 @@
+/*
+ *  The order of the following two lines is important.
+ *
+ *  SUPPRESS_FOPEN_REDEFINITION is defined before including git-compat-util.h
+ *  to avoid the redefinition of fopen within git-compat-util.h. This is
+ *  necessary since fopen is a macro on some platforms which may be set
+ *  based on compiler options. For example, on AIX fopen is set to fopen64
+ *  when _LARGE_FILES is defined. The previous technique of merely undefining
+ *  fopen after including git-compat-util.h is inadequate in this case.
+ */
+#define SUPPRESS_FOPEN_REDEFINITION
+#include "../git-compat-util.h"
+
+FILE *git_fopen(const char *path, const char *mode)
+{
+	FILE *fp;
+	struct stat st;
+
+	if (mode[0] == 'w' || mode[0] == 'a')
+		return fopen(path, mode);
+
+	if (!(fp = fopen(path, mode)))
+		return NULL;
+
+	if (fstat(fileno(fp), &st)) {
+		fclose(fp);
+		return NULL;
+	}
+
+	if (S_ISDIR(st.st_mode)) {
+		fclose(fp);
+		errno = EISDIR;
+		return NULL;
+	}
+
+	return fp;
+}